Certainly agree that the key to staying afloat on the sand is tire pressure. Being reluctant to drop below 15 psi is critical... yet many people are reluctant because there is no conventient pump station when you get back onto pavement or they don't carry an airtank.
But even dropping down to 10 psi doesn't guarantee a safe ride. Consider that some vehicles may weigh as much as 50% more than others.... and they still ride on similar tires... or even smallr ones. My suburban has skinny 225's while many folks run Wranglers with 245's. People driving tanks on tiny treads have to be more cautious about where they venture.... and that's why i carry the boards in the back. I don't need them when I'm running around in my Isuzu Trooper.